Mark J. Bassett

The inheritance of intensified anthocyanin expression (IAE) in a syndrome of plant organs of common bean (Phaseolus vulgaris L.) was investigated. A selection from accession line G07262, having white flowers with blue veins on the wing petals and a long, white micropyle stripe on black seedcoats, was used as the source of IAE syndrome. G07262 was crossed with three genetic tester stocks based on Florida dry bean line 5-593, which has the flower and seedcoat genotype T P [C r] Z J G B V Rk. The tester stocks were 5-593 (black seed and bishops violet flowers), t z bip bipunctata BC1 5-593 (a partly colored seedcoat), and v BC2 5-593 (mineral brown seedcoat and white flowers). Analysis of the F1 and F2 data from the test cross G07262 × t z bip bipunctata BC1 5-593 demonstrated that 1) G07262 has genotype t pmicV; 2) genotype t/t prevents expression of IAE syndrome by a dominant gene (Prpi-2) carried cryptically by G07262, i.e., T/-is required for expression of the gene; and 3) Prpi-2 may (preliminary data) express blue veins on white flowers with t V. From the cross with v BC2 5-593, an F4 selection for white flowers with red banner back and mineral brown seedcoats (due to v) was made. When the F4 selection was crossed with 5-593, analysis of the F2 progeny demonstrated that G07262 carries a dominant gene for IAE syndrome, which expresses with V/- but not with v/v. From the test cross 5-593 × G07262, a series of additional cycles of selection and test crosses (including the dark red kidney tester cub v rkd BC1 5-593) were made, and two new two-colored seedcoat patterns were developed that have never been previously reported. In a test cross with one of them, F2 data demonstrated that the dominant gene for IAE syndrome from G07262 is independent of the C locus, and the gene symbol Prpi-2 is proposed for this IAE syndrome gene to distinguish it from the previously reported IAE syndrome gene [cuPrpi]. A gene symbol reconciliation was made for all previous work with inheritance of IAE syndrome and purple pod genes without the syndrome.

Mark J. Bassett

Mark J. Bassett

The effects of gri on seed coat and flower color were investigated in a study using Lamprecht line V0400 (PI 527735) as the known source of gri. Seed and flower color data were taken on observations of F2, BC1-F2, and BC2,-F2 populations from crosses of V0400 with the recurrent parent S-593. Segregation was observed for a unique flower color pattern: wing petals have a very pale tinge of blue (laelia), and the banner petal has two violet dots (≈3- to 4-mm diameter) on a nearly white background. This very pale laelia flower color cosegregates with gray-white seed coats produced by gri. Furthermore, the very pale laelia color depends on the action of V for expression and is extinguished by v, which produces pure white flowers. Thus, it was demonstrated that the very pale laelia flower color, for which Lamprecht tentatively proposed the gene symbol vpal, is not controlled by an allele at V but is a pleiotropic effect of gri. It was also demonstrated that Lamprecht line V0060 (PI 527717) carries vlae, not v, as indicated by the genotypic notes accompanying the Lamprecht seed collection.

Mark J. Bassett

A cross was made between gri (gray-white seedcoat) and p (pure-white seedcoat) using genetic stocks gri BC2 5-593 and p BC2 5-593 developed to carry only a single recessive allele for seedcoat color in an otherwise all-dominant genetic background. The recurrent parent, 5-593, is a Florida dry-bean breeding line with bishops-violet flowers, determinate habit, small seed size, shiny black seeds, and seedcoat genotype T Mar P [C r] D J G B V Rk. The F1 progeny from the above cross between gri and p had the flower color pattern and seedcoat color of the griseoalbus character (gri), but had less intense color expression. Therefore, I hypothesized that gri is an allele at the P locus (allelic interaction). The hypothesis of allelism was confirmed in the F2, which failed to segregate for bishops-violet flowers and black seed, i.e., no complementation was evident. The symbol pgri is proposed for the new allele at P, where the dominance series is P > pgri > p. The gene for gray-white seeds in gri BC2 5-593 was shown to be allelic to Lamprecht's gri gene in V0059 (PI 527716).

Mark J. Bassett

The red common bean (Phaseolus vulgaris L.) seedcoat colors produced by the dominant gene R and the dark red kidney gene rkd are very similar, making it difficult for breeders of red bean varieties to know which genotype is in their materials. A protocol employing test crosses with genetic stocks having known genotypes for seedcoat colors was developed to identify genotypes with either of two very similar dark red seedcoat colors: garnet brown controlled by rkd and oxblood controlled by R. Twenty bean varieties and breeding lines were test crossed with genetic tester stocks cu BC3 5-593 and b v BC3 5-593, and four of the varieties were test crossed with [? R] b v BC3 5-593. Analysis of the seedcoat colors and patterns in the F1 progenies from the test crosses demonstrated that unambiguous identification of the genotypes of the two dark red colors could be achieved using the cu BC3 5-593 and b v BC3 5-593 testers. The dark red color (garnet brown) of the Small Red market class materials was demonstrated to be produced by rkd, and the dark red color (oxblood) of `Jacobs Cattle' was demonstrated to be produced by R. A Light Red Kidney market class stock was derived from `Redkloud' and used in two crosses: cub v rk BC1 5-593 × b v BC3 5-593 and cub v rk BC1 5-593 × cu BC3 5-593. Classification of the F2 progenies demonstrated that the cu gene does not entirely prevent rk red color from being modified by V. The interactions of rk, rkd, and R with C, cu, G, B, and V are discussed, and previous literature concerning those interactions is critically reviewed.

Mark J. Bassett

Studying the genetics of seedcoat color in common bean (Phaseolus vulgaris L.) in F2 progenies is very difficult because of complex epistatic interactions, and the analysis is complicated further by multiple allelism, especially at the C locus. An alternative approach is to study seedcoat genetics by analyzing the F1 progeny of test crosses between a variety with unknown seedcoat genotype and genetic tester stocks with known genotypes. Twenty varieties, 18 with known genotype at C, were test crossed with the genetic tester stock cu BC3 5-593, where 5-593 is a recurrent parent with seedcoat genotype P [C r] D J G B V Rk. The resulting F1 progenies were classified into seven phenotypic classes and discussed. The crosses g B v BC3 5-593 × cu BC3 5-593 and cu BC3 5-593 × v BC3 5-593 were made and the F2 progeny classified for flower color and seedcoat color and pattern. No tiny cartridge buff flecks were observed in the segregants with C/cuv/v, whereas C/cuV/- always showed such flecks. The contrasting seedcoat color expression at C in different environmental conditions is discussed.

Mark J. Bassett

Anecdotal evidence exists for nonflatulence among Chilean Manteca and Coscorrón market classes of common bean (Phaseolus vulgaris L.), and there is an hypothesis that the seedcoat color may be associated with superior digestibility. The inheritance of seedcoat color in `Prim', a Manteca market-class dry bean, was investigated using a protocol employing genetic interpretation of seedcoat colors in the F1 from testcrosses of `Prim' with a series of tester stocks. Most of the genetic tester stocks were constructed previously by backcrossing selected recessive alleles for seedcoat color into a recurrent parent (5-593) with seedcoat color genotype P [C r] D J G B V Rk Asp. The genetic tester stocks included two varieties, `Masterpiece' and `V0687', and testers constructed on the 5-593 background, viz., j BC2 5-593, d j BC2 5-593, asp BC2 5-593, b v BC2 5-593, v BC2 5-593, and cu BC3 5-593. The seedcoat color genotype of `Prim' was found to be P [C r] d j G b vlae. The implications of this genotype for pigment chemistry are discussed.

Mark J. Bassett

The inheritance of two new induced mutations for spindly branch was investigated in common bean (Phaseolus vulgaris L.). Each mutant was found to be controlled by a recessive gene. Allelism tests were performed beween a previously reported spindly branch mutant (sb) and the two new spindly branch mutants; the new mutants were found to be nonallelic to sb and to each other. The gene symbols sb-2 and sb-3 are proposed for the new mutants. Repulsion phase F2 linkage tests were made for all nine combinations of reclining foliage (rf) and sb among the two mimic mutant series rf, rf-2, rf-3 and sb, sb-2, sb-3. No linkages were detected.

Mark J. Bassett

The inheritance of corona and hilum ring color of common bean (Phaseolus vulgaris L.) was investigated in the reciprocal cross `Wagenaar' (a Canario market class dry bean) × `Mayocoba' (Mayocoba market class dry bean), where both parents were known to have seedcoat color genotype P [C r] gy J g b vlaeRk. `Wagenaar' has greenish yellow (GY) seedcoat (due to gy) except for purple (dark) corona (due to vlae) and reddish brown hilum ring (due to J), whereas `Mayocoba' has an entirely GY seedcoat. Seeds produced on the F1 progeny plants had GY corona and reddish brown hilum ring. The F2 segregated for three phenotypic classes, the two parental classes and the F1 class, but the segregation did not fit a 1:2:1 segregation ratio due to disturbed segregation. F3 progeny tests of 35 randomly selected F2 parents demonstrated that the two parental classes were true breeding and the F1 class segregated again (as in the F2) for the same three phenotypic classes. In spite of variable expressivity of GY color and disturbed segregation, the data support a single gene hypothesis, for which the tentative symbol Chr is proposed. Chr is dominant for changing purple corona to GY, but recessive for changing reddish brown hilum ring to GY. Thus, only one gene, Chr, controls the difference in seedcoat color between the market classes Canario and Mayocoba. An allelism test between Chr and Z (hilum ring color factor) is needed before a formal proposal for Chr can be made.